In general, mobile terminals can be freely used during moving without being limited by a place. Mobile communication terminals such as mobile phones and personal digital assistants (PDAs) called personal mobile terminals are typical mobile terminals. Thus, the term “mobile terminal” used in the present specification includes all the above devices. However, for the convenience of explanation, the following description focuses on the PDA.
In a complicated and diversified society, individuals need to store or maintain personal information. To meet such a need, various products are presently released in the market. One of the products is a PDA.
The PDA, called as a pocket computer, refers to all compact devices of a palm size having calculation and information storing and search functions for personal or business use. The PDA is widely used for schedule calendar and address information.
In particular, PDAs for industrial use are widely used especially in logistics industry and the market is gradually growing. The industrial PDA is equipped with various business functions as a barcode scanner and a card checker that is not provided in a general PDA. The industrial PDA has merits of efficient operations of delivery, file management, and related businesses.
For example, in insurance companies, various insurance related businesses such as customer information management, customer search, schedule management, interview records management, celebration data search, and fund account statement process can be directly processed by an insurance agent on the spot using the industrial PDA. In hospitals, not only treatment records, medical history, and prescriptions of a patient but also images such as an X-ray image and graphic materials can be input or searched for using the industrial PDA carried by medical staffs without limits in time and place. Also, in the business of police, the outside control business of traffic policemen and night guards is performed using the industrial PDA so that fines for violations of traffic regulations that must be paid 2-3 days after the issue of a fine can be instantly paid at financial institutes. Thus, time for the outside control business can be remarkably reduced.
Thus, as it can be seen that the industrial PDA is used in the above-described various industrial fields, the industrial PDA needs requirements over a predetermined level to endure in an industrial environment not in a general environment, unlike a general PDA. That is, when the industrial PDA is used in an industrial site, the industrial PDA can be used in a cold store at a temperature below −10° C. or outdoors for a long time. Also, since the industrial PDA can be toughly handled by a user such as a mailman, functions such as anti-shock, waterproof, and anti-heat/cold are needed for a competitive PDA.
In particular, since the industrial PDA is used in the industrial environment of a rather tough condition, a waterproof structure is required. Also, it may frequently occur that the industrial PDA bumps against a hard floor due to careless handling by a user. Accordingly, since various problems, for example, circuit parts in the industrial PDA may be deviated from the original positions or electric connection is cut off so that a battery cannot be charged, the industrial PDA must have an anti-shock function against a physical impact.
The industrial PDA has a connection terminal portion that is provided at a lower surface of a casing to connect to an external device such as a cradle. The connection terminal portion is electrically connected to a main board. Due to the above structure, the industrial PDA can charge a battery connected to the main board by receiving external power and also can transmit or receive data.
To implement a waterproof structure related to the connection terminal portion, intrusion of water into a gap of the connection terminal portion must be prevented. Nevertheless, the anti-shock function must not be degraded by the implementation of the waterproof structure.
However, in a conventional mobile terminal, since the connection terminal portion is manufactured in a complicated insertion type and connected to the external device, it is difficult to implement the waterproof structure. When the waterproof structure is implemented, it is a problem that the electric connection between the connection terminal portion and the external device is easily cut off due to degradation of the anti-shock function of the connection terminal portion, that is, an impact.
Thus, an improved structure to firmly maintain the electric connection between the connection terminal portion and the main board in spite of an impact and simultaneously implement a waterproof structure of the connection terminal portion is needed.